ARISTOTILE, ARISTOTLE. Aristotle of Stagira, 384-322 B.C., was the son of Nicomachus, physician to Amyntas II, king of Macedonia. He was Plato's pupil from 367 until Plato's death in 347 B.C. In that year Philip destroyed Stagira, and in 342 he invited Aristotle to Macedonia to become Alexander's tutor. When Alexander started out for Persia in 335, Aristotle returned to Athens, where he opened a school of philosophy and natural sciences. He was charged with impiety after Alexander's death in 323 and left Athens. He died in Chalcis the following year at the age of sixty-three (Diogenes Laertius V.i).

Medieval scholars knew a number of Aristotle's works. Michael Scot (c. 1175-c. 1235) translated from Arabic into Latin at Toledo, before 1220, the Liber animalium(The Book of Animals), De caelo et mundo(On the Heavens), and De anima (On the Soul) from ibn-Rushd's commentaries. At the same time, Alfredus Anglicus did a version of three chapters forming an appendix of the fourth book of the Meteorology, translated from ibn-Sina's Arabic Shifa, or The Healing. Alfred's translation of On Plants was the only Latin version known in the West. Gerard of Cremona did a version of The Physics and the Posterior Analytics in the twelfth century. Alexander Neckham used Michael Scot's translation of Liber animalium in his De natura rerum, completed in 1217. Medieval scholars thus knew more of Aristotle than of Plato, and Dante termed him il maestro di color che sanno, the master of those who know (Inf IV.131). Aristotle was so popular that he was identified simply as "the Philosopher." But the Arab elements in the Latin translations of his works were soon found to be irreconcilable with Christian doctrine, and the Paris Council forbade the teaching of Aristotle's works on natural philosophy in 1210. The prohibition was extended to the Metaphysics in 1215. Pope Gregory clarified the ban in 1231, but the statutes of the Faculty of the University of Paris mention several works as subjects for examinations in 1254. The prohibition did not extend further than Paris. Aristotelian studies flourished at Toulouse, and the Parva naturalia, a collection of essays on the senses and on sleep and dreams, was a prescribed text in the arts curriculum at Oxford after 1340.

The Clerk would rather have twenty books of Aristotle than fiddle and psaltery, GenProl 293-296, a collection that would have included texts with commentaries. The cost of such a library would have been forty pounds in medieval currency and about $8,000 in modern money. The magic mirror, which the strange knight presents to Cambyuskan, reminds the courtiers of Aristotle, who wrote on mirrors, SqT 232-235, a reference to Aristotle's Physics. Dante mentions this work in Inf XI.101. Aristotle and Plato are mentioned as writers on the law stating that every object has a natural place that it tries to reach, HF II.757-764, the medieval explanation of the law of gravity. The passage probably refers to Aristotle's Physics, VIII.3, 4. The definition of sound, HF II.765-781, is a possible rendering of a similar theory found in St. Thomas Aquinas's commentary on Aristotle's On the Soul II.viii.445-446. Aristotle appears as a source for the idea that if men had eyes like the lynx, they would be able to preceive things hidden from mortal eyes, Bo III, Prosa 8.40. Pindar's Nemean Ode X.61 tells the story of Lynceus, who was famous for his keen eyesight, and perhaps Boethius means Lynceus and not the lynx. No source for this idea has been found in Aristotle. Lady Philosophy discusses final cause and chance, Bo V; Prosa 1.62, and gives a brief summary of Aristotle's Physics, II.4-5. Lady Philosophy also quotes Aristotle, Bo V, Prosa 6.30, on the eternity of the world from On the Heavens (De caelo) I.279B: the world never began and it will never cease. Aristotle here reverses the opinions of two previous philosophers, Empedocles and Heraclitus. The lines "Vertu is the mene/As Etik says," LGW F 165-166, seem to refer to the Nichomachean Ethics, in which Aristotle discusses happiness and virtue. Gower refers to Aristotle's advice to Alexander to keep the mean between avarice and prodigality (Confessio Amantis VII.2025-2057), another possible reference in contemporary writing to the Ethics. John Norton-Smith shows that Chaucer could have known Aristotle's Ethics in at least five versions in Latin, several Latin and vernacular adaptations, and one good complete translation in Old French. Robert Grosseteste did the first Latin translation of all ten books of the Vetus Translatio of the Ethics c. 1245, and Walter Burley wrote a commentary between 1340 and 1345, which Chaucer could have known. The Ethics could also be found in summary and verbatim quotations in Vincent of Beauvais, Speculum Doctrinale IV.x.xvi.

Much of Aristotle's work on dreams, memory and recollection, sleeping, and waking in his Parva naturalia appear in ibn-Sina's Qanun, or Canon; On Dreams III is paraphrased in ibn-Sina's Commentary on the Soul, and in Vincent of Beauvais, Speculum naturale, XXVI.i. If Chaucer was not familiar with the Parva naturalia itself, he could have become acquainted with its ideas from Vincent of Beauvais, for he seems to have known other aspects of Vincent's work. The Squire's definition of sleep as "the norice of digestion," SqT 347, appears in On Sleeping and Waking III. Pertelote says that when humors are abundant in a man, the fumes of overeating determine the images that appear in dreams, NPT 2923-2925; this notion echoes OnDreams III. Pertelote remarks that some dreams are caused by melancholy, which produces black images in sleep, NPT 2933-2936; Aristotle says that dreams are morbid in the melancholic, the feverish, and the intoxicated, On Dreams III. The dream that follows the narrator's reading of Africanus is caused by his activity during waking hours, i.e., his reading of The Dream of Scipio, as well as by mental disturbance, PF 85-98. The "wery huntere" stanza that follows, inspired by Claudian's preface to De raptu Proserpinae, also illustrates Aristotle's definition of dreams: they are mental pictures arising from sense impressions during the day, On Dreams III, and some mental pictures that appear in sleep are associated with waking actions, On Prophecy in Sleep I. Pandarus says that Troilus's dream is produced by melancholy, Tr V.358-360; he asserts that some people say dreams come through impressions, having something in mind, Tr V.372-374, a paraphrase of Aristotle, that dreams are sense impressions occurring in sleep, On Dreams III. [Alocen: Averrois: Avycen: Vitulon]